The delivery of active agents to surfaces must occur in sufficient amounts to allow the agent to achieve its purpose. However it can be difficult to achieve sufficient delivery of agents to a wide variety of surfaces, both biological and non-biological, due to difficulties in maintaining sufficient concentration in the operational environment and to permeability barrier effect of many target surfaces.
Furthermore, there is a general push, due to economic, health-related and environmental reasons, to use less of many active agents in a given composition. This provides further problems in relation to the delivery of active agents, as there may not be a sufficient concentration gradient to allow the active agent to diffuse effectively and to penetrate or partition into or onto the surface.
Chemical penetration enhancers can facilitate changes in barrier permeability. However, the use of chemical penetration enhancers can be problematic due to unknown interaction with the active agent and the potential for adverse side effects such as irritation of skin and mucosal surfaces or unwanted interactions with the cosmetic and or functional properties of barriers.
A diffusion enhancement technique which may be used for some biological surfaces is iontophoresis, in which an electrical energy gradient is used to accelerate the charged target active agent(s) across the skin or barrier. However, iontophoresis is only suitable to specific active agents with certain ionic structures and can be injurious to certain biological barriers due to exchange ion degradation. Additionally, iontophoresis requires the use of intimate electrical contact and adhesive electrodes, which are not suitable for all target surfaces or barriers.
Other techniques to create mobility and/or direction in the movement of active agent(s) such as magnetokinetics and magnetophoresis are possible, however they have been difficult to implement due to poor performance, high hardware and energy requirements, and cost.
There is therefore a need for methods to enhance the availability, diffusion characteristic and penetration of active agents into surfaces using physical technologies which can replace or at (east compliment the previously known chemical and physical penetration enhancers.
The present invention seeks to provide an improved delivery process for active agents that have a pharmaceutical, nutraceutical, biopharmaceutical, cosmeceutical, cosmetic, anti-biological (anti-bacterial, anti-viral, antifungal, anti-parasitic, insecticidal etc), detergent, cleaning, bleaching, dying, fragrancing, conditioning or polishing activity, in a manner which increases the directional penetration of these agents into biological and non-biological surfaces.
The previous discussion of the background art was intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.